DEMO MANUAL DC1640A LTC3833EUDC High Efficiency Step-Down DC/DC Converter DESCRIPTION Demonstration circuit 1640A is a 1.5V/20A synchronous buck converter operating with a switching frequency of 300kHz over an input voltage range of 4.5V to 14V. The demo board comes in two versions. The A version uses inductor DCR current sensing with an iron powder inductor for high efficiency. The B version uses a 2mΩ /1% sense resistor for accurate current sensing with a low DCR ferrite inductor. The fixed on-time valley current mode topology of the LTC3833 allows for a fast load step response (see Figures 4 and 5). The load step response can be tested with the onboard load step circuit and a bench pulse generator. Other features of the board include a MODE jumper to program either DCM or CCM with light or no load, a PLLIN input for synchronizing the converter to an external clock, a TRACK/SS pin, a PGOOD pin and an EXTVCC pin. The demo board uses a high density, two sided drop-in layout. The entire converter, excluding the bulk output and input capacitors, fits within a compact 1.4” × 0.6” area on the board. The package style for the LTC3833EUDC is a 3mm × 4mm 20-lead QFN with an exposed ground pad. Design files for this circuit board are available at http://www.linear.com/demo L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. PERFORMANCE SUMMARY PARAMETER (TA = 0°C to 85°C) CONDITION VALUE Minimum Input Voltage 4.5V Maximum Input Voltage 14V Output Voltage IOUT = 0A to 20A Switching Frequency Efficiency DCR Sense Version (A) RSENSE Version (B) 1.5V ±2% 300kHz VIN = 12V, VOUT = 1.5V, IOUT = 20A; See Figures 2 and 3 89.4% 88.8% dc1640af 1 DEMO MANUAL DC1640A QUICK START PROCEDURE Demonstration circuit 1640A is easy to set up to evaluate the performance of the LTC3833EUDC. Please refer to Figure 1 for proper measurement equipment setup and follow the procedure below. 1.With power off, connect the input supply, load and meters as shown in Figure 1. Preset the load to 0A and VIN supply to be 0V. Place jumpers in the following positions: JP1 JP2 RUN MODE ON CCM 2.Adjust the input voltage to be between 4.5V to 14V. VOUT should 1.5V ± 2%. 3.Next, apply 20A load and recheck VOUT. 4. Once the DC regulation is confirmed, observe the output voltage ripple, load step response, efficiency and other parameters. Note 1. To measure the output voltage ripple, use the BNC connector labeled VOUT. Note 2. Do not apply the load from the VO_SNS+ turret to the VO_SNS– turret. This will damage the converter. These turrets are only intended to monitor VOUT across COUT4 which is the point of regulation. + VOUT V – * IOUT IIN A A + VIN SUPPLY + LOAD – DC1640 F01 – VIN V + * THE VO_SNS+ and VO_SNS– TURRETS MONITOR VOLTAGE ACROSS COUT4 WHICH IS THE POINT OF REGULATION. MONITOR THE VOLTAGE ACROSS COUT2 FOR MORE ACCURATE EFFICIENCY MEASUREMENTS. Figure 1. Proper Measurement Equipment Setup dc1640af 2 DEMO MANUAL DC1640A QUICK START PROCEDURE Demonstration circuit 1640A has a simple load step circuit consisting of a MOSFET and sense resistor. To apply a load step, follow the steps below. 1.Preset the amplitude of a pulse generator to 0.0V and the duty cycle to 5% or less. 2.Connect the VOUT and LOAD STEP BNC connectors to the oscilloscope. Use a short cable to minimize noise pickup. 3.Connect the output of the pulse generator to the PULSE GEN turret and connect the return to the GND turret. 4.With the converter running, slowly increase the amplitude of the pulse generator output to provide the desired load step pulse height. The scaling for the LOAD STEP signal is 10mV/Amp. 95 100 90 DCR SENSE 90 80 85 80 DCR SENSE VERSION (–A): L = WÜRTH 744355047 (0.47µH, DCR = 0.9mΩ ±10%) 75 RSENSE VERSION (–B): L = COILTRONICS FP1308R3-R44 (0.44µH, DCR = 0.18mΩ ±20%) RSENSE = 2mΩ 70 EFFICIENCY (%) EFFICIENCY (%) RSENSE QTOP = RENESAS RJK0305DPB QBOTTOM = RENESAS RJK0330DPB 0 5 10 15 LOAD CURRENT (A) 20 70 60 RSENSE DCM RSENSE CCM 50 40 DCR SENSE VERSION (–A): L = WÜRTH 744355047 (0.47µH, DCR = 0.9mΩ ±10%) DCR SENSE DCM 30 20 10 25 DC1640 F02 Figure 2. Efficiency Curves for the DC1640A in CCM. 0 0.01 DCR SENSE CCM 0.1 QTOP = RENESAS RJK0305DPB QBOTTOM = RENESAS RJK0330DPB RSENSE VERSION (–B): L = COILTRONICS FP1308R3-R44 (0.44µH, DCR = 0.18mΩ ±20%) RSENSE = 2mΩ 1 LOAD CURRENT (A) 10 100 DC1640 F03 Figure 3. Efficiency Curves for the DC1640A in CCM and DCM. dc1640af 3 DEMO MANUAL DC1640A QUICK START PROCEDURE 50µs/DIV 1.5VO (AC) 50mV/DIV LOAD STEP 10A/DIV 50µs/DIV 1.5VO (AC) 50mV/DIV 20A LOAD STEP 10A/DIV 10A DC1640 F04 Figure 4. 10A to 20A to 10A Load Step Response of the DC1640A-A (DCR Sense) at VIN = 12V. COUT = 2x Sanyo 2R5TPE330M9 || 2x 100µF, X5R, 6.3V, 1206; L = 0.47µH; FSW = 300kHz 20A 10A DC1640 F05 Figure 5. 10A to 20A to 10A Load Step Response of the DC1640A-B (RSENSE) at VIN = 12V. COUT = 2x Sanyo 2R5TPE330M9 || 2x 100µF, X5R, 6.3V, 1206; FSW = 300kHz; L = 0.44µH dc1640af 4 DEMO MANUAL DC1640A PARTS LIST DEMO CIRCUIT 1640A-A (DCR SENSE) ITEM QUANTITY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 Cap X7R 0.22µF 16V 10% 0603 AVX 0603YC224KAT2A 2 2 C3, C9 Cap X7R 0.1µF 16V 10% 0603 AVX 0603YC104KAT2A 3 1 C4 Cap X7R 0.01µF 16V 10% 0603 AVX 0603YC103KAT2A 4 1 C5 Cap C0G 100pF 50V 5% 0603 AVX 06035A101JAT2A 5 1 C6 Cap C0G 470pF 50V 10% 0603 AVX 06035A471KAT2A 6 1 C7 Cap X5R 4.7µF 16V 10% 0805 AVX 0805YD475KAT2A 7 3 CIN1, CIN2, CIN6 Cap X5R 22µF16V 10% 1210 Murata GRM32ER61C226KE20L 8 1 CIN4 Cap SVP 180µF 16V 30mΩ ESR Sanyo 16SVP180MX 9 2 COUT1, COUT2 Cap X5R 100µF 6.3V 20% 1206 Murata GRM31CR60J107ME39L 10 2 COUT3, COUT4 Cap POSCAP 330µF 2.5V 20% 7343 Sanyo 2R5TPE330M9 11 1 D1 Diode Schottky 30V SOD323 Central Semi CMDSH-3TR 12 1 L1 Inductor 0.47µH Würth Elektronik 744355047 13 1 Q1 MOSFET Power N-CH LFPAK Renesas RJK0305DPB 14 1 Q2 MOSFET Power N-CH LFPAK Renesas RJK0330DPB 15 1 R1 Res 100k 1/16W 5% 0603 Yageo RC0603JR-07100KL 16 2 R10, R11 Res 10 1/16W 5% 0603 Yageo RC0603JR-0710RL 17 2 R13, R17 Res 0 1/16W 0603 Yageo RC0603FR-070RL 18 1 R15 Res 13k 1/16W 1% 0603 Yageo RC0603FR-0713KL 19 1 R18 Res 137k 1/16W 1% 0603 Yageo RC0603FR-07137KL 20 1 R20 Res 2.2 1/16W 5% 0603 Yageo RC0603JR-072R2L 21 2 R21, R8 Res 10k 1/16W 1% 0603 Yageo RC0603FR-0710KL 22 2 R4, R9 Res 0 1/16W 0603 Yageo RC0603FR-070RL 23 1 R6 Res 15k 1/10W 1% 0603 Yageo RC0603FR-0715KL 24 1 R7 Res 2.15k 1/16W 1% 0603 Yageo RC0603FR-072K15L 25 1 RS1 Res 0.000 2512 Tepro RN5326 26 1 U1 IC LTC3833EUDC Linear Technology LTC3833EUDC#PBF Additional Circuit Components 1 0 C2, C8, C10 Cap 0603 OPT 2 0 CIN3 Cap SVP-F8 OPT 3 0 CIN5 Cap 1210 OPT 4 0 COUT5, COUT6 Cap 1206 OPT 5 0 Q3, Q4 MOSFET Power N-CH LFPAK OPT 6 1 Q5 MOSFET N-CH 30-V (D-S) DPAK-TO252AA Vishay SUD50N03-12P-E3 7 1 R22 Res Chip 10k 1/16W 1% 0603 Yageo RC0603FR-0710KL 8 1 R23 Res 0.01 2% 2010 IRC LRC-LRF2010LF-01-R010-G 9 0 R2, R3, R12, R14, R5, R16, R19 Res 0603 OPT Hardware for Demo Board Only 1 10 E1 to E10 Testpoint Turret .094” Mill-Max 2501-2-00-80-00-00-07-0 2 4 J1, J2, J3, J4 Jack Banana Keystone 575-4 3 2 J5, J6 Conn BNC 5 Pins Connex 112404 4 2 JP1, JP2 Shunt 2MM Center Samtec 2SN-BK-G 5 2 JP1, JP2 Header 2MM Single Row 3 Pin Samtec TMM-103-02-L-S 6 4 Stand-Off Nylon 0.50” Keystone 8833 (Snap-On) dc1640af 5 DEMO MANUAL DC1640A PARTS LIST DEMO CIRCUIT 1640A-B (RSENSE) ITEM QUANTITY REFERENCE PART DESCRIPTION MANUFACTURER/PART NUMBER Required Circuit Components 1 1 C1 Cap X7R 1000pF 50V 5% 0603 AVX 06035C102JAT2A 2 2 C3, C9 Cap X7R 0.1µF 16V 10% 0603 AVX 0603YC104KAT2A 3 1 C4 Cap X7R 0.01µF 16V 10% 0603 AVX 0603YC103KAT2A 4 1 C5 Cap C0G 100pF 50V 5% 0603 AVX 06035A101JAT2A 5 1 C6 Cap C0G 470pF 50V 10% 0603 AVX 06035A471KAT2A 6 1 C7 Cap X5R 4.7µF 16V 10% 0805 AVX 0805YD475KAT2A 7 3 CIN1, CIN2, CIN6 Cap X5R 22µF16V 10% 1210 Murata GRM32ER61C226KE20L 8 1 CIN4 Cap SVP 180µF 16V 30mΩ ESR Sanyo 16SVP180MX 9 2 COUT1, COUT2 Cap X5R 100µF 6.3V 20% 1206 Murata GRM31CR60J107ME39L 10 2 COUT3, COUT4 Cap Poscap 330µF 2.5V 20% 7343 Sanyo 2R5TPE330M9 11 1 D1 Diode Schottky 30V SOD323 Central Semi CMDSH-3TR 12 1 L1 Inductor 0.44µH Cooper Bussmann FP1308R3-R44-R 13 1 Q1 MOSFET Power N-CH LFPAK Renesas RJK0305DPB 14 1 Q2 MOSFET Power N-CH LFPAK Renesas RJK0330DPB 15 1 R1 Res Chip 100k 1/16W 5% 0603 Yageo RC0603JR-07100KL 16 2 R10, R11 Res Chip 10 1/16W 5% 0603 Yageo RC0603JR-0710RL 17 1 R14 Res Chip 0 1/16W 0603 Yageo RC0603FR-070RL 18 1 R15 Res Chip 16.5k 1/16W 1% 0603 Yageo RC0603FR-0716K5L 19 1 R18 Res Chip 137k 1/16W 1% 0603 Yageo RC0603FR-07137KL 20 2 R2, R3 Res Chip 10 1/10W 1% 0603 Yageo RC0603FR-0710RL 21 1 R20 Res Chip 2.2 1/16W 5% 0603 Yageo RC0603JR-072R2L 22 2 R21, R8 Res Chip 10k 1/16W 1% 0603 Yageo RC0603FR-0710KL 23 2 R4, R9 Res Chip 0 1/16W 0603 Yageo RC0603FR-070RL 24 1 R6 Res Chip 15k 1/10W 1% 0603 Yageo RC0603FR-0715KL 25 1 RS1 Res Chip 0.002Ω 1W 1% 2512 Vishay WSL25122L000FEA 26 1 U1 IC LTC3833EUDC Linear Technology LTC3833EUDC#PBF Additional Circuit Components 1 0 C2, C8, C10 Cap 0603 OPT 2 0 CIN3 Cap SVP-F8 OPT 3 0 CIN5 Cap 1210 OPT 4 0 COUT5, COUT6 Cap 1206 OPT 5 0 Q3, Q4 MOSFET Power N-CH LFPAK OPT 6 1 Q5 MOSFET N-CH 30-V (D-S) DPAK-TO252AA Vishay SUD50N03-12P-E3 7 1 R22 Res Chip 10k 1/16W 1% 0603 Yageo RC0603FR-0710KL 8 1 R23 Res 0.01 2% 2010 IRC LRC-LRF2010LF-01-R010-G 9 0 R2, R3, R12, R14, R5, R16, R19 Res 0603 OPT Hardware for Demo Board Only 1 10 E1 to E10 Testpoint Turret .094” Mill-Max 2501-2-00-80-00-00-07-0 2 4 J1, J2, J3, J4 Jack Banana Keystone 575-4 3 2 J5, J6 Conn BNC 5 Pins Connex 112404 4 2 JP1, JP2 Shunt 2MM Center Samtec 2SN-BK-G 5 2 JP1, JP2 Header 2MM Single Row 3 Pin Samtec TMM-103-02-L-S 6 4 Stand-Off Nylon 0.50” Keystone 8833 (Snap-On) dc1640af 6 Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. D C B * JP1 E8 R16 OPT R19 OPT VIN C8 OPT * R14 * R17 INTVCC 0 R4 470pF 1 -A (DCR SENSE) -B (RSENSE) ASSY L1 R6 15K 2 WURTH 744355047 (0.47uH) COILTRONICS FP1308R3-R44-R (0.44uH) 2. INSTALL SHUNTS ON JUMPERS AS SHOWN. 1. ALL RESISTORS ARE IN OHMS, 0603. ALL CAPACITORS ARE IN MICROFARADS, 0603. * R15 C2 OPT FSW = 300kHz C6 100pF 0.01uF C5 C4 R5 OPT NOTES: UNLESS OTHERWISE SPECIFIED PLLIN E7 E5 E4 1 2 3 EXTVCC ON OFF RUN TRK/SS PGOOD 6 5 4 3 2 1 21 0.22uF 1000pF C1 R18 137K R8 10K 2.15K OPT R7 C10 OPT SGND RT VRNG ITH TRKSS VOSNS+ VOSNS- U1 LTC3833EUDC VOUT S- * C1 * R2 * S+ R3 3 OPT OPT R12 0 OPT R13 C9 2.2 0.1uF 16V R21 10K 11 12 13 14 15 16 R20 INTVCC PGND BG SW TG BOOST 20 VOUT RUN 7 R1 100K 19 SNSEXTVCC 8 INTVCC 18 SNS+ MODE/PLLIN 9 A 17 PGOOD VIN 10 0 R9 INTVCC JP2 OPT 0 4 0 OPT R17 DCM CCM MODE R14 1 2 3 C7 4.7uF 16V 0805 C3 0.1uF 16V 4 4 OPT 10 R2,R3 D1 CMDSH-3 4 5 Q1 RJK0305DPB Q2 RJK0330DPB 1 2 3 5 4 4 5 Q3 OPT Q4 OPT RS1 CIN1 22uF 16V 1210 VIN 5 * L1 * R7 S- * VOUT R12 * R13 S+ 6 * J5 2512 RS1 6 THIS CIRCUIT IS PROPRIETARY TO LINEAR TECHNOLOGY AND SUPPLIED FOR USE WITH LINEAR TECHNOLOGY PARTS. LINEAR TECHNOLOGY HAS MADE A BEST EFFORT TO DESIGN A CIRCUIT THAT MEETS CUSTOMER-SUPPLIED SPECIFICATIONS; HOWEVER, IT REMAINS THE CUSTOMER'S RESPONSIBILITY TO VERIFY PROPER AND RELIABLE OPERATION IN THE ACTUAL APPLICATION. COMPONENT SUBSTITUTION AND PRINTED CIRCUIT BOARD LAYOUT MAY SIGNIFICANTLY AFFECT CIRCUIT PERFORMANCE OR RELIABILITY. CONTACT LINEAR TECHNOLOGY APPLICATIONS ENGINEERING FOR ASSISTANCE. CUSTOMER NOTICE 13.0K 16.5K R15 DCR SENSE FILTER / DIVIDER CIN2 22uF 16V 1210 0.000 Ohm 2512, TEPRO RN5326 0.002 Ohm 2512, VISHAY WSL25122L000FEA 1 2 3 5 1 2 3 5 1 2 3 3 5 4 3 2 2 COUT2 100uF 6.3V 1206 MIKE S. APP ENG. SCALE = NONE NC PCB DES. APPROVALS COUT3 330uF 2.5V 7343 CIN5 OPT 1210 DATE: N/A SIZE R22 10K E10 E9 GND PULSE GEN COUT6 OPT 1206 TECHNOLOGY 1630 McCarthy Blvd. Milpitas, CA 95035 Phone: (408)432-1900 www.linear.com Fax: (408)434-0507 LTC Confidential-For Customer Use Only LOAD STEP CIRCUIT R23 0.01 2010 GND VOUT 1.5V / 20A VIN- GND DATE 9/27/10 7 LTC3833EUDC DEMO CIRCUIT 1640A-A/B 9/27/10 IC NO. 8 SHEET 1 OF 1 2 REV. HIGH EFFICIENCY STEP-DOWN DC-DC CONVERTER TITLE: SCHEMATIC 1 1 Q5 MIKE S. VIN 4.5V - 14V VIN+ 8 APPROVED ONLY APPLY LOAD FROM J3 TO J4 J4 J3 E6 180uF 16V J2 J1 E3 VO_SNS- VO_SNS+ + CIN4 COUT5 OPT 1206 OPT SVP-F8 + CIN3 COUT4 330uF 2.5V 7343 VOUT + VOUT CIN6 22uF 16V 1210 E2 E1 PRODUCTION FAB 2 - REVISION HISTORY DESCRIPTION REV ECO 7 SUD50N03-12P + R11 10 LOAD STEP J6 10mV / A 5% DUTY CYCLE MAX 1 COUT1 100uF 6.3V 1206 R10 10 5 4 3 2 2 3 1 D C B A DEMO MANUAL DC1640A SCHEMATIC DIAGRAM dc1640af 7 DEMO MANUAL DC1640A DEMONSTRATION BOARD IMPORTANT NOTICE Linear Technology Corporation (LTC) provides the enclosed product(s) under the following AS IS conditions: This demonstration board (DEMO BOARD) kit being sold or provided by Linear Technology is intended for use for ENGINEERING DEVELOPMENT OR EVALUATION PURPOSES ONLY and is not provided by LTC for commercial use. As such, the DEMO BOARD herein may not be complete in terms of required design-, marketing-, and/or manufacturing-related protective considerations, including but not limited to product safety measures typically found in finished commercial goods. As a prototype, this product does not fall within the scope of the European Union directive on electromagnetic compatibility and therefore may or may not meet the technical requirements of the directive, or other regulations. If this evaluation kit does not meet the specifications recited in the DEMO BOARD manual the kit may be returned within 30 days from the date of delivery for a full refund. THE FOREGOING WARRANTY IS THE EXCLUSIVE WARRANTY MADE BY THE SELLER TO BUYER AND IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED, IMPLIED, OR STATUTORY, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. EXCEPT TO THE EXTENT OF THIS INDEMNITY, NEITHER PARTY SHALL BE LIABLE TO THE OTHER FOR ANY INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES. The user assumes all responsibility and liability for proper and safe handling of the goods. Further, the user releases LTC from all claims arising from the handling or use of the goods. Due to the open construction of the product, it is the user’s responsibility to take any and all appropriate precautions with regard to electrostatic discharge. Also be aware that the products herein may not be regulatory compliant or agency certified (FCC, UL, CE, etc.). No License is granted under any patent right or other intellectual property whatsoever. LTC assumes no liability for applications assistance, customer product design, software performance, or infringement of patents or any other intellectual property rights of any kind. LTC currently services a variety of customers for products around the world, and therefore this transaction is not exclusive. Please read the DEMO BOARD manual prior to handling the product. Persons handling this product must have electronics training and observe good laboratory practice standards. Common sense is encouraged. This notice contains important safety information about temperatures and voltages. For further safety concerns, please contact a LTC application engineer. Mailing Address: Linear Technology 1630 McCarthy Blvd. Milpitas, CA 95035 Copyright © 2004, Linear Technology Corporation dc1640af 8 Linear Technology Corporation LT 1210 • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2010